Need relief from chronic pain? Marijuana may not help after all, studies say

When it comes to treating chronic pain or post-traumatic stress disorder, an increasing number of people are turning to marijuana for relief. However, those efforts may be in vain, because new research has found little evidence to support its effectiveness.

A group of scientists from the Veterans Health Administration recently completed two meta studies, which were both published in Annals of Internal Medicine, to determine the usefulness of the drug. To do so, they reviewed data that linked the use of cannabis with chronic pain and PTSD alleviation.

First, they reviewed 27 pain trials that examined the use of the plant as a remedy. They concluded that there was “insufficient evidence” to prove its effectiveness for symptoms related to illnesses, including cancer and multiple sclerosis. They did, however, see some improvement for those with neuropathic pain.

“We found low-strength evidence that cannabis preparations with precisely defined THC–cannabidiol content may alleviate neuropathic pain, but insufficient evidence in populations with other types of pain. Most studies are small, many have methodological flaws, and the long-term effects are unclear given the brief follow-up of most studies,” the report said.

In fact, they had sufficient evidence linking marijuana use with an increased risk of car accidents, psychotic symptoms and short-term cognitive impairment.

The researchers next took a look at five studies and reviews that assessed cannabis use for treating PTSD. They found that the evidence here was also lacking. One portion of a study even showed that symptoms worsened for veterans who used the drug during the assessment.

“Overall, we found insufficient evidence regarding the benefits and harms of plant-based cannabis preparations for patients with PTSD. The body of literature currently available is limited by small sample sizes, lack of adjustment for important potential confounders, cross-sectional study designs, and a paucity of studies with non–cannabis-using control groups,” the study said.

Currently, medical marijuana is legal in 28 states and Washington D.C., and up to 80 percent of people who request it say they use it for pain management. However, the latest research suggests there isn’t enough proof that it works.

“The current studies highlight the real and urgent need for high-quality clinical trials in both of these areas,” Dr. Sachin Patel, a psychiatry researcher at Vanderbilt University Medical Center, told Reuters.

“If cannabis is being considered for medical use,” she continued, "it should certainly be after all well-established treatments have failed.”